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Mutations in an Arabidopsis Mitochondrial Transcription Termination Factor–Related Protein Enhance Thermotolerance in the Absence of the Major Molecular Chaperone HSP101

Publication Type:Journal Article
Year of Publication:2012
Authors:Kim, M, Lee, U, Small, I, Francs-Small, CColas Des, Vierling, E
Journal:The Plant Cell
Volume:24
Issue:8
Date Published:2012
ISBN Number:10404651
Abstract:

The molecular chaperone heat shock protein101 (HSP101) is required for acquired thermotolerance in plants and other organisms. To identify factors that interact with HSP101 or that are involved in thermotolerance, we screened for extragenic suppressors of a dominant-negative alíele of Arabidopsis thaliana HSP101, hot1-4. One suppressor, shoti (for suppressor of hot1-4 1), encodes a mitochondrial transcription termination factor (mTERF)-related protein, one of 35 Arabidopsis mTERFs about which there is limited functional data. Missense (shoti-1) and T-DNA insertion (shoti-2) mutants suppress the hot1-4 heat-hypersensitive phenotype. Furthermore, shot1-2 suppresses other heat-sensitive mutants, and shot1-2 alone is more heat tolerant than the wild type. SHOT1 resides in mitochondria, indicating it functions independently of cytosolic/nuclear HSP101. Microarray analysis suggests altered mitochondrial function and/or retrograde signaling in shoti-2 increases transcripts of other HSPs and alters expression of redox-related genes. Reduced oxidative damage is the likely cause of shoti thermotolerance, indicating HSP101 repairs protein oxidative damage and/or reduced oxidative damage allows recovery in the absence of HSP101. Changes in organelle-encoded transcripts in shoti demonstrate that SHOT1 is involved in organelle gene regulation. The heat tolerance of shoti emphasizes the importance of mitochondria in stress tolerance, and defining its function may provide insights into control of oxidative damage for engineering stress-resistant plants.

URL:http://www.jstor.org/stable/41692805
Short Title:The Plant Cell
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